Componentize TopSites, TopSitesBackend, TopSitesDatabase

components/history/core/browser/top_sites_backend.cc

Index: components/history/core/browser/top_sites_backend.cc
diff --git a/chrome/browser/history/top_sites_backend.cc b/components/history/core/browser/top_sites_backend.cc
similarity index 70%
rename from chrome/browser/history/top_sites_backend.cc
rename to components/history/core/browser/top_sites_backend.cc
index fdecd1c869ef93b657aa09365ea803e89e31f791..37b721bf7fea205a403e6dc113ae9230e26a2212 100644
--- a/chrome/browser/history/top_sites_backend.cc
+++ b/components/history/core/browser/top_sites_backend.cc
@@ -2,80 +2,72 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/history/top_sites_backend.h"
+#include "components/history/core/browser/top_sites_backend.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_path.h"
+#include "base/location.h"
 #include "base/memory/ref_counted.h"
+#include "base/single_thread_task_runner.h"
 #include "base/task/cancelable_task_tracker.h"
-#include "chrome/browser/history/top_sites_database.h"
-#include "content/public/browser/browser_thread.h"
+#include "components/history/core/browser/top_sites_database.h"
 #include "sql/connection.h"
 
-using content::BrowserThread;
-
 namespace history {
 
-TopSitesBackend::TopSitesBackend()
-    : db_(new TopSitesDatabase()) {
+TopSitesBackend::TopSitesBackend(
+    const scoped_refptr<base::SingleThreadTaskRunner>& db_task_runner)
+    : db_(new TopSitesDatabase()), db_task_runner_(db_task_runner) {
+  DCHECK(db_task_runner_);
 }
 
 void TopSitesBackend::Init(const base::FilePath& path) {
   db_path_ = path;
-  BrowserThread::PostTask(
-      BrowserThread::DB, FROM_HERE,
-      base::Bind(&TopSitesBackend::InitDBOnDBThread, this, path));
+  db_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&TopSitesBackend::InitDBOnDBThread, this, path));
 }
 
 void TopSitesBackend::Shutdown() {
-  BrowserThread::PostTask(
-      BrowserThread::DB, FROM_HERE,
-      base::Bind(&TopSitesBackend::ShutdownDBOnDBThread, this));
+  db_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&TopSitesBackend::ShutdownDBOnDBThread, this));
 }
 
 void TopSitesBackend::GetMostVisitedThumbnails(
     const GetMostVisitedThumbnailsCallback& callback,
     base::CancelableTaskTracker* tracker) {
   scoped_refptr<MostVisitedThumbnails> thumbnails = new MostVisitedThumbnails();
-
   tracker->PostTaskAndReply(
-      BrowserThread::GetMessageLoopProxyForThread(BrowserThread::DB).get(),
-      FROM_HERE,
-      base::Bind(&TopSitesBackend::GetMostVisitedThumbnailsOnDBThread,
-                 this,
+      db_task_runner_.get(), FROM_HERE,
+      base::Bind(&TopSitesBackend::GetMostVisitedThumbnailsOnDBThread, this,
                  thumbnails),
       base::Bind(callback, thumbnails));
 }
 
 void TopSitesBackend::UpdateTopSites(const TopSitesDelta& delta) {
-  BrowserThread::PostTask(
-      BrowserThread::DB, FROM_HERE,
+  db_task_runner_->PostTask(
+      FROM_HERE,
       base::Bind(&TopSitesBackend::UpdateTopSitesOnDBThread, this, delta));
 }
 
 void TopSitesBackend::SetPageThumbnail(const MostVisitedURL& url,
                                        int url_rank,
                                        const Images& thumbnail) {
-  BrowserThread::PostTask(
-      BrowserThread::DB, FROM_HERE,
-      base::Bind(&TopSitesBackend::SetPageThumbnailOnDBThread, this, url,
-                 url_rank, thumbnail));
+  db_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&TopSitesBackend::SetPageThumbnailOnDBThread, this,
+                            url, url_rank, thumbnail));
 }
 
 void TopSitesBackend::ResetDatabase() {
-  BrowserThread::PostTask(
-      BrowserThread::DB, FROM_HERE,
+  db_task_runner_->PostTask(
+      FROM_HERE,
       base::Bind(&TopSitesBackend::ResetDatabaseOnDBThread, this, db_path_));
 }
 
 void TopSitesBackend::DoEmptyRequest(const base::Closure& reply,
                                      base::CancelableTaskTracker* tracker) {
-  tracker->PostTaskAndReply(
-      BrowserThread::GetMessageLoopProxyForThread(BrowserThread::DB).get(),
-      FROM_HERE,
-      base::Bind(&base::DoNothing),
-      reply);
+  tracker->PostTaskAndReply(db_task_runner_.get(), FROM_HERE,
+                            base::Bind(&base::DoNothing), reply);
 }
 
 TopSitesBackend::~TopSitesBackend() {
@@ -84,7 +76,8 @@ TopSitesBackend::~TopSitesBackend() {
 }
 
 void TopSitesBackend::InitDBOnDBThread(const base::FilePath& path) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::DB));
+
+  DCHECK(db_task_runner_->BelongsToCurrentThread());
   if (!db_->Init(path)) {
     LOG(ERROR) << "Failed to initialize database.";
     db_.reset();
@@ -92,13 +85,13 @@ void TopSitesBackend::InitDBOnDBThread(const base::FilePath& path) {
 }
 
 void TopSitesBackend::ShutdownDBOnDBThread() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::DB));
+  DCHECK(db_task_runner_->BelongsToCurrentThread());
   db_.reset();
 }
 
 void TopSitesBackend::GetMostVisitedThumbnailsOnDBThread(
     scoped_refptr<MostVisitedThumbnails> thumbnails) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::DB));
+  DCHECK(db_task_runner_->BelongsToCurrentThread());
 
   if (db_) {
     db_->GetPageThumbnails(&(thumbnails->most_visited),
@@ -130,7 +123,7 @@ void TopSitesBackend::SetPageThumbnailOnDBThread(const MostVisitedURL& url,
 }
 
 void TopSitesBackend::ResetDatabaseOnDBThread(const base::FilePath& file_path) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::DB));
+  DCHECK(db_task_runner_->BelongsToCurrentThread());
   db_.reset(NULL);
   sql::Connection::Delete(db_path_);
   db_.reset(new TopSitesDatabase());